A variety of medical conditions require draining a patient's bladder by inserting a catheter through the urethra into the bladder. In a simple case the catheter is a flexible tube having a single lumen. Absent a reliable retention arrangement, this catheter will slide out of the urethra and is hence commonly removed after each drainage. This single-use protocol provides a substantial risk of injury to and infection of both the urinary tract and the bladder.
The well-known Foley indwelling catheter is retained by a balloon at the proximal end of the catheter. The balloon is inflated through a first of two lumens, to a diameter greater than the urethra's. This retains the indwelling catheter and allows for continuous drainage through the second lumen. Because the second lumen is necessarily narrower than a single lumen in a catheter having the same outer diameter, drainage may be impeded. The very narrow drainage lumen can also clog, resulting in acute pain, and removal of the catheter. Moreover, the Foley catheter can fail to deflate resulting in an acutely painful forcible withdrawal of the still inflated balloon.
Thus, there is an unfulfilled need for an arrangement for retaining the proximal end of a urethral catheter in a patient's bladder without requiring a balloon or multiple lumens.